1. Technical Field
The present invention relates generally to a Peripheral Component Interconnect Express (PCIe) switch apparatus and a method of controlling the connection thereof and, more particularly, to a PCIe switch apparatus and a method of controlling the connection thereof, which enable conversion between an electrical signal and an optical signal to be performed within the PCIe switch apparatus so as to control a long-distance communication interface between a local host and a PCIe-based device.
2. Description of the Related Art
Generally, methods of connecting to a PCIe-based device over a long distance include a method of extending a connection range using a PCIe cable, a method of respectively exploiting PCIe switches for local and remote devices and connecting PCIe signals between the PCIe switches to each other using an optical medium, and a method of directly converting PCIe signals generated by a local device into optical signals and connecting the optical signals over a long distance.
The method using the PCIe cable is limited in a connection distance and in an operating speed because of the use of electrical signals, and is also disadvantageous in that packets may be lost due to the attenuation of signals. Further, the method of exploiting PCIe switches for local and remote devices is disadvantageous in that resources are wasted and a delay time is increased because of the use of unnecessary duplicate PCIe switches. Furthermore, the method of directly converting PCIe signals into optical signals and connecting the optical signals over a long distance is disadvantageous because it is impossible to achieve protocol standards, such as the sensing of a receiver using electrical signals and the change in the level of electrical signals, which are required by PCIe protocols.
FIG. 1 is a diagram showing the configuration of a PCIe connection apparatus using the PCIe cable extension technology among the above-described conventional technologies. Referring to FIG. 1, a PCIe slot connector present in a PCIe cable extension card 20 is connected to a PCIe slot connector present in a local host 10, such as a server or a Personal Computer (PC). In this case, signals present in the PCIe slot connector are converted by a PCIe signal converter 21 for conversion between the PCIe slot connector signals and cable signals so that the PCIe slot connector signals meet PCIe cable standards. In a remote place, a PCIe slot extension board 30 must be provided in order to connect to a PCIe-based device 40. In the PCIe slot extension board 30, a PCIe signal converter 31 for conversion between PCIe slot connector signals and cable signals is present to provide signal matching therebetween. A problem with a PCIe interface apparatus having this configuration is that electrical signals are used without being changed, so that the problem of signal attenuation cannot be overcome when a large number of signals are used, there is interference between signals, and the cable is extended over a long distance. Further, the distance of the signal connection is limited to 1 to 1.5 m, and the thickness of the cable for remotely connecting signals also acts as a non-negligible factor interfering with extending over a long distance. Therefore, the efficiency of signal transmission is deteriorated, so that an effective counter plan for improving signal transmission efficiency is required.